Evaluation of the auxiliary diagnosis value of antibodies assays for the detection of novel coronavirus (SARS-Cov-2)

Abstract

Background: The spread of an novel coronavirus (SARS-CoV-2, previously named 2019-nCoV) has already taken on pandemic proportions, affecting over 100 countries in a matter of weeks. Elucidating the diagnostic value of different methods, especially the auxiliary diagnosis value of antibodies assays for SARS-CoV-2 infection is helpful for improving the sensitivities of pathogenic-diagnosis, providing timely treatment, and differentiating the infected cases from the healthy, thus preventing further epidemics. Methods: Medical records from 38 patients with confirmed SARS-CoV-2 infection in the Second People's Hospital of Fuyang from January 22, 2020 to February 28, 2020 were collected and retrospectively analyzed. Specimens including throat swabs, sputum and serum were collected during the hospitalization period, viral RNAs and serum IgM-IgG antibodies to SARS-CoV-2 were measured respectively. The detectability of different methods as well as the auxiliary diagnosis value of antibodies test for SARS-CoV-2 infection were analyzed.Results: Among 38 patients, the total seropositive rate for IgM and IgG was 50.0% and 92.1%, respectively. Two patients remained seronegative throughout the course of illness. In the early phase of illness, the RNA test for sputum specimens possessed the highest detectability(92.3%), followed by the the RNA test for throat swabs (69.2%), and the antibodies assays presented lower positive rates(IgM, 23.0%, IgG, 53.8%).While, the sensitivity of antibodies assays overtook that of RNA test since day 8 after onset (IgM, 50.0%; IgG, 87.5%). Of note, the positive rate of throat swabs was only 13.0% for cases in later phase (≥15 d.a.o), and the sensitivities of IgM and IgG rose to 52.2% and 91.3%, respectively. Combined use of antibodies assay and qRT-PCR at the same time was able to improve the sensitivities of pathogenic-diagnosis, especially for the throat swabs group at the later stage of illness. Moreover, most of these cases with undetectable viral RNA in throat swabs specimens at the early stage of illness were able to be IgM/IgG seropositive after 7 days. Conclusions:The antibodies detection against SARS-CoV-2 offers vital clinical information for physicians, and could be used as an effective supplementary indicator

Diagnostic accuracy estimates for COVID-19 RT-PCR and Lateral flow immunoassay tests with Bayesian latent class models

“…The latter observation of increasing positive detection rate for IgG and/or IgM with a steady and potentially slight decrease for SARS-CoV-2 viral load has also been observed elsewhere 35,36 . SeIgG/M is higher than SeRT-PCR after the second week, which is also in line with recent evidence that the sensitivity of antibody assays overtook the RNA test on day 8 after the onset of symptoms 37 . Further, other authors also found a steep increase for antibodies, particularly in the second week, that is accompanied by a slight decrease in the probability of detection with nasopharyngeal swabs/ bronchoalveolar/sputum PCR over the first three weeks after symptom onset 38 .…”

Diagnostic accuracy of serological tests for covid-19: systematic review and meta-analysis

“…In total, 4696 records based on screening of titles or abstracts and 235 after full text review were excluded. Forty studies totalling 73 study arms15161718192021222324252627282930313233343536373839404142434445464748495051525354 met the inclusion criteria. Table 1 summarises the studies by test method; the sum of the number of studies exceeds 40 because some evaluated more than one method.…”

“…Table 1 summarises the studies by test method; the sum of the number of studies exceeds 40 because some evaluated more than one method. Seventy per cent (28/40) of the studies were from China,16171819202122232425262728293031323334353839404145464748 8% (3/40) from Italy,153643 and the remainder from the United States (3/40),425052 Denmark (1/40),51 Spain (1/40),37 Sweden (1/40),53 Japan (1/40),44 the United Kingdom (1/40),49 and Germany (1/40) 5433…”

Effect of a Previous History of Antiretroviral Treatment on Clinical Picture of Patients with Co-infection of SARS-CoV-2 and HIV: A Preliminary Study

“…Leukocytes (Â10⁹/L) 3.5-9.5 4.4 (3.5-5.3) 5 (25%) 4.5 (3.9-5.3) 3.7 (3.0-5.8) 0.343 Neutrophils (Â10⁹/L) 1.8-6.3 2.5 (2.2-3.2) 2 (10%) 2.5 (2.2-3.2) 2.5 (2.0-3.9) 0.970 Lymphocytes (Â10⁹/L) 1.1-3.2 1.1 (0.9-1.9) 9 (45%) 1.3 (1.0-1.9) 1.1 (0.7-1.9) 0.545 Hemoglobin ( SARS-CoV-2 provides important immunological evidence and can be an effective supplementary indicator in diagnosing the suspected cases with no detectable viral RNA (Gao et al, 2020). In our study, some patients tested negative for RT-PCR nucleic acid and IgM/IgG antibodies on admission, and the results of the viral RNA test turned positive a few days later.…”